1. Field of the Invention
The present disclosure generally relates to retaining filters and more particularly to a filter housing for use in an HVAC duct, wherein the filter housing can operably accommodate any of a plurality of filters having different dimensions along the direction of flow in the duct.
2. Description of Related Art
Conventional forced air household furnaces or central air conditioners include a return duct to direct air into a central unit for conditioning by either heating or cooling the air and an outlet duct for distribution of the conditioned air from the central unit throughout the home. The return duct or other structure though which air flows typically incorporates a filter within the air stream for removing dust and other particulate matter from the air stream. As air passes through the filter, the matter is removed to prevent distribution through the home as well as to avoid contamination of the central unit.
Several types of filters exist for removal of matter from the air. The most common variety is a standard, rectangular panel replaceable filter, which is composed of a random arrangement of fibers. Panel filters are usually approximately one inch thick and are inserted into a correspondingly sized opening in the duct. These filters operate by trapping particles within the randomly oriented fibers. These filters are used in a majority of American homes and are able to capture large particles, thereby helping to protect the central units and minimize the amount of dust on the heating or cooling equipment. Once these filters become saturated with dirt, dust, and the like, the filters are removed from the duct and replaced with a new filter.
Alternatives to the replaceable panel filter include replaceable and/or reusable pleated filters, high efficiency pleated filters, high efficiency particulate air (HEPA) filters, and washable fiberglass filters. Each of these alternatives typically has a different thickness (dimension along the flow path). That is, all the filters are sized to fit within a cross section of a given duct (such as 14×16) but have thicknesses that can range from about one inch to 5 inches thick.
Another system for removing particles from air in a home heating or cooling system is an electronic air cleaner. Duct mounted electronic air cleaners typically use an electrostatic precipitation systems. Such systems are extremely efficient, especially in the 0.1 to 10 micron size range, and advantageously create a very low pressure drop. Because trapped particles on collecting plates can build up and reduce the electrostatic field and, hence, collection efficiency, the cleaners should be cleaned weekly or monthly. While electronic air cleaners are more effective than the above-described fiber-based filters (with the exception of HEPA filters), they are relatively very expensive by comparison. Currently, they also are designed as a separate special unit that is installed between the central unit and the return duct and have a width typically between four and six inches. The special unit cannot fit within the standard filter opening found in most return ducts and also require relatively complicated installation, which is typically performed by a professional.
Electronic air cleaners are sometimes known to include conventional fiber-based filters. These hybrid filters can have a dimension from approximately 3 inches to 5 inches along the flow path.
Each type of filter has advantages and disadvantages. However, as each filter size requires a unique fitting within the duct. Thus, once a consumer selects a given filter type, absent a rebuild of the ventilation system, the consumer is without the ability to change filter types.
There is a need for a filter housing that can accommodate different filter dimensions (as measured along the flow path), without requiring a modification of a ventilating duct. The need further exists for a filter housing that operably retains any of a variety of filter types having a common periphery, wherein the thickness of the filter may vary substantially between filter types.